Apparatus for treatment of cardiac valves and method of its manufacture

ABSTRACT

A prosthetic valve including a replacement valve having a tubular valve body wall, an expandable stent having a framework with first and second ends, and suturing holding the framework to the valve body at the first and second ends. The suturing at the first end is colored differently from the suturing at the second end.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional application havingSer. No. 60/629,468 filed Nov. 19, 2004, entitled “APPARATUS FORTREATMENT OF CARDIAC VALVES AND METHOD OF ITS MANUFACTURE,” whichapplication is incorporated herein by reference in its entirety. Thisapplication is a divisional application of U.S. Pat. No. 8,562,672,filed Nov. 18, 2005, the disclosure of which is incorporated herein byreference in its entirety.

TECHNICAL FIELD

The invention relates generally to treatment of cardiac valve diseaseand more particularly to replacement of malfunctioning pulmonary valves.

BACKGROUND

Recently, there has been increasing interest in minimally invasive andpercutaneous replacement of cardiac valves. In the context of pulmonaryvalve replacement, U.S. Patent Application Publication Nos. 2003/0199971A1 and 2003/0199963 A1, both filed by Tower, et al., describe a valvedsegment of bovine jugular vein, mounted within an expandable stent, foruse as a replacement pulmonary valve. The replacement valve is mountedon a balloon catheter and delivered percutaneously via the vascularsystem to the location of the failed pulmonary valve and expanded by theballoon to compress the valve leaflets against the right ventricularoutflow tract, anchoring and sealing the replacement valve. As describedin the articles: Percutaneous Insertion of the Pulmonary Valve,Bonhoeffer, et al., Journal of the American College of Cardiology 2002;39: 1664-1669 and Transcatheter Replacement of a Bovine Valve inPulmonary Position, Bonhoeffer, et al., Circulation 2000; 102: 813-816,the replacement pulmonary valve may be implanted to replace nativepulmonary valves or prosthetic pulmonary valves located in valvedconduits. Surgical procedures for percutaneous pulmonary valveimplantation are described in Khambadkone et al., Percutaneous PulmonaryValve Implantation in Humans, Circulation, Pp. 1189-1197 (Aug. 23,2005).

Other implantables and implant delivery devices are disclosed inpublished U.S. Patent Application No. 2003-0036791-A1 and EuropeanPatent Application No. 1 057 460-A1.

SUMMARY

The present invention is particularly directed to valves of the typegenerally described in the Tower et al. and Bonhoeffer, et al.references cited above as used within a prosthetic valve or valvesystem. However, the invention may also be useful in other types ofvalves, particularly valves which take the form of a generally tubularvalve body of natural or synthetic material, in which valve leaflets areprovided. Examples of such other valves include those described in U.S.Pat. Nos. 6,719,789 and 5,480,424, both issued to Cox.

In one aspect of the invention, an improved suturing technique isemployed to attach the valved venous segment or other replacement valveto its associated stent. In at least one aspect, in order to preventinward bowing of the walls of the venous segment or other substantiallytubular valve body, the tissue of the segment or other tubular valvebody is attached to the stent at all or substantially all of the angledportions of the stent. Alternatively, sutures may be distributed aboutthe stent at other locations such that no portion of the venous wall orother tubular valve body is more than a few millimeters from a suture.

In another aspect of the invention a prosthetic valve is provided thatincludes a replacement valve having a substantially tubular valve bodywall, an expandable stent having a framework including a plurality of“V” structures, each having a base, and sutures located at each baseholding the valve body wall to the stent. The sutures are preferably nofurther than 7 mm from one of the sutures. The replacement valve can bea valved vein segment and the valve body wall can be the vein segment'swall. The valved vein segment can be a valved segment of bovine jugularvein.

In another aspect of the invention, an assembly consisting of a venoussegment or other replacement valve and an associated stent iscolor-coded to allow for easier determination of a particularconfiguration. For example, such a visual indicator can be used toidentify which end of the valve is the inflow end and which end of thevalve is the outflow end. In a particularly preferred embodiment, thesuturing at the outflow end and/or inflow end of the valve is colored tomatch that portion of an associated delivery device intended to beadjacent the end of the valve when properly mounted to the device. Othermethods of providing a colored marking may be provided in addition to orin substitution for sutures.

In another aspect of the invention, a prosthetic valve and deliverysystem is provided, with the valve being mountable to the deliverysystem in correct or incorrect manners. The prosthetic valve comprises areplacement valve having a substantially tubular valve body wall, anexpandable stent having a framework with first and second ends, andsutures holding the framework to the valve body wall at the first andsecond ends. The sutures at the first end are colored differently fromthe suturing at the second end. The delivery system is provided with acolored component of generally the same color as the sutures at thefirst end of the framework and the colored component is located suchthat when the valve is correctly mounted to the delivery system, thecolored component is adjacent to the first end of the framework.Alternatively, the system may be provided with a colored marker locatedat one of the first and second ends of the framework, rather than thecolored sutures. When the valve is correctly mounted to the deliverysystem, the colored component is adjacent to the colored marker. In afurther alternative, the replacement valve (rather than the stentframework) has first and second ends, wherein one of the ends includes acolored marker that is located relative to the delivery system such thatwhen the valve is correctly mounted, the colored component is adjacentto the colored marker.

BRIEF DESERTION OF THE DRAWINGS

The present invention will be further explained with reference to theappended Figures, wherein like structure is referred to by like numeralsthroughout the several views, and wherein:

FIG. 1 is a top perspective view of an exemplary stent for use inconjunction with the present invention;

FIG. 2 is cross-sectional side view of an exemplary valved venoussegment for use in conjunction with the present invention;

FIG. 3 is a perspective view of an exemplary method of marking thevenous segment prior to beginning the process of suturing the venoussegment to its associated stent;

FIG. 4 is a top view of an exemplary method for placing of sutures formarking the position of valve commissures of the venous segment, such asthe venous segment of FIG. 3;

FIGS. 5-11 illustrate several exemplary sequential steps that can beperformed in providing an assembly including a stent and a venoussegment, where each of these Figures is summarized in further detail asfollows:

FIG. 5 is a top view of an assembly showing an exemplary initialplacement of a stent over the venous segment, with both elementspositioned on a mandrel;

FIG. 6 is a top view of the assembly of the type illustrated in FIG. 5,and further illustrating an exemplary final positioning of the venoussegment relative to the stent;

FIG. 7 is a top view of the assembly of the type illustrated in FIG. 6,and further illustrating a technique of suturing the ends of the stentto the venous segment;

FIG. 8 is a top view of an assembly of the type illustrated in FIG. 7,and further illustrating both of the stent ends secured to the veinsegment;

FIG. 9 is a top view of an assembly of the type illustrated in FIG. 8and further illustrating an exemplary technique for trimming the venoussegment to the approximate length of the stent;

FIG. 10 is a top view of an assembly of the type illustrated in FIG. 9and further showing the venous segment after being trimmed to match thestent;

FIG. 11 is a top view of an assembly of the type illustrated in FIG. 10and further illustrating the final steps of suturing the stent to thevenous segment;

FIG. 12 is a top view of an exemplary delivery system for an assembledstented venous segment; and

FIG. 13 is a top view illustrating an exemplary operation of thedelivery system of FIG. 12.

DETAILED DESCRIPTION

Referring now to the Figures, wherein the components are labeled withlike numerals throughout the several Figures, and initially to FIG. 1,one configuration of an exemplary stent 10 for use in conjunction withthe present invention is illustrated. The stent 10 as illustratedcorresponds generally to a stent of the type described in theabove-cited Tower, et al., and Bonhoeffer et al. references, forexample. The stent 10 may be fabricated of platinum, stainless steel orother biocompatible metal. Stent 10 may alternatively be fabricatedusing wire stock as described in the above-cited Tower, et al.applications, or the stent 10 may be produced by machining the stentfrom a metal tube, as is commonly employed in the manufacturing ofstents. The number of wires, the positioning of such wires, and variousother features of the stent can vary considerably from that shown in thefigures. The stent can be used in conjunction with bovine jugular veinsegments in which the stent would typically be in the range of about 16mm to 20 mm in diameter when expanded. The specifics of the stent canvary widely within the scope of the invention, such that many otherknown generally cylindrical stent configurations may be used and areconsidered to be within the scope of the invention.

The stent 10, like most expandable cylindrical stents, generally takesthe form of a series of zig-zag ring structures, such as are indicatedby reference number 18. The structures 18 are coupled longitudinally toone another to form a generally cylindrical-shaped structure, althoughit is understood that the structures 18 can form be arranged in an atleast slightly oval or elliptical shape. Each ring structure 18 takesthe form of a series of adjacent generally straight sections (e.g., 12,14) which each meet one another at one end at a curved or angledjunction (e.g., junction 16) to form a “V” or “U” shaped structure. Forpurposes of the present application, this structure will be referred toas a “V”, and the included junction (e.g., junction 16) is referred toas the base of the “V”. The relatively straight portions (e.g., straightsections 12, 14) of the stent between the bases of the “V”s, arereferred to herein as the “arms” of the “V” or simply as “arms”. Whilethe angled junctions illustrated take the form of relatively sharplyangled junctions, the “V” terminology is also intended to include moregradually curved junctions as well, such as might be shaped more like a“U” with arms that are angled away from each other at least slightly.

Stents of the type illustrated are generally sized to be in the 16 mm to20 mm diameter range when expanded, and are configured so that the basesof the “V”s are preferably spaced no further than about 8 mm from oneanother around the circumference of the stent. It should also beunderstood that although the ring structures are coupled to one anotherat the base of each “V” in the illustrated embodiment, stents employedaccording to the present invention may employ ring structures coupled toone another at fewer bases of their “V”s or coupled to one another byadditional and/or different structures, such as longitudinal members ofthe type disclosed in U.S. Pat. No. 6,773,455, issued to Allen, et al.,U.S. Pat. No. 6,641,609, issued to Globerman and in U.S. Pat. No.6,136,023, issued to Boyle. The invention also includes within its scopethose stents in which wires are formed into zig-zags and wound spirallyto produce a cylindrical structure, as in U.S. Pat. No. 6,656,219,issued to Wictor or woven stents as disclosed in U.S. Pat. No.4,655,771, issued to Wallsten.

Stents of the type described above, such as stent 10, can be assembledinto a pulmonary valve assembly in accordance with the methods of theinvention described herein. The pulmonary valve assemblies can beutilized in for purcutaneous replacement of cardiac valves, for example.One exemplary method for assembling a stented valve generally firstincludes preparation of a vein segment, then a subsequent mounting orattachment of the prepared vein segment to the stent, which aredescribed below in further detail.

FIG. 2 illustrates a cross-sectional view of a vein segment 20 of thetype that is appropriate for use in construction of the valve assembly.The embodiment illustrated may exemplify a preserved bovine jugular veinof the type described in the above-cited Bonhoeffer, et al. and Tower,et al. references, but other vessels or donor species may alternativelybe employed. Alternatively, other replacement valves with substantiallytubular valve bodies may be substituted. The vein segment 20 asillustrated includes leaflets 22 extending from the wall of the veinsegment 20 from leaflet bases 24 (i.e., bottoms of leaflets 22) tocommissures 26, which define the outer meeting points of the furthestdownstream portions of the leaflets 22. The vein segments used for thepresent invention are generally referred to herein as being tubular orsubstantially tubular in shape, which are typical shapes in which veinsegments are provided, although the vein segments can be somewhatirregular or differently shaped, such as elliptical or the like. In anycase, the description of the vein segments or valves herein as beingtubular or generally tubular is meant to encompass any such shapes. Thevein segment 20 further includes an inflow end 28 through which bloodwill enter the vein segment 20 and an outflow end 27 through which bloodwill exit the vein segment 20.

The vein segment 20 preferably has three leaflets 22, but may optionallyhave less. The leaflets 22 of the vein segment 20, in their closedposition, should have the capability to hold fluid for at least fiveseconds, and there should preferably be no branches in that portion ofthe vein wall which will ultimately be located in the stent.

In a particular procedure, a vein segment 20 of an appropriate length isselected for attachment to a desired stent. The wall of the vein segment20 is then measured to determine its wall thickness. As described in theabove-cited Bonhoeffer, et al and Tower, et al. references, for example,if the vein segment 20 has a wall thickness greater than about 0.5 mm,the vein segment 20 will preferably be thinned to leave a wall thicknessof no more than about 0.5 mm. This thinning process may be performed ina variety of ways, one of which includes placing the vein onto amandrel, then trimming the adventitial tissue. One method of performingthe thinning includes pulling the adventitia from the wall of the vein,then using a cutting instrument, such as scissors, to snip or cut thetissue fibers until as much of the tissue fibers are removed asnecessary to achieve a desired wall thickness. After the thinningprocess is complete, the tissue may appear to be relatively translucent.

Either prior to or subsequent to the thinning operation described above,the vein segment 20 can be trimmed to a desired length for attachment toa stent in order to easier perform the steps of securing the veinsegment 20 to a stent 10. This step would not be necessary if the veinsegment 20 has been provided in the desired length, such as from sometype of preparation location. In at least one exemplary process in whichvein segment trimming is desired, the vein segment 20 is trimmed at afirst location 30 spaced from inflow end 28 and/or at a second location32 spaced from output end 27 to leave a minimum of about 15 mm of tissuefrom the tops of the commissures 26 and the bottoms 24 of the leaflets22 to the ends of the vein segment 20. If the vein segment 20 is trimmedin this way, the inflow end 28 and outflow end 27 will then be shiftedto these new locations where the vein segment 20 was trimmed. It isunderstood that the distance from the tops of the commissures 26 and thebottoms 24 of the leaflets 22 to the ends 27, 28 can be more or lessthan 15 mm, as desired or necessary for attachment to differently sizedstents, where the 15 mm distance is desirable and common for at leastsome valve assemblies. In any case, it is desirable to provide a longenough vein segment 20 to accomplish the remaining steps of the assemblymethod that is not so long that it interferes with the attachmentprocedure.

Next, FIG. 3 illustrates one exemplary manner of locating and markingthe top of each commissure 26 on the outside of the vein segment 20.First, a forceps 44 is positioned close to, but at a minimum of 1 mmabove the top of each commissure 26 of vein segment 20. The forceps 44are squeezed together to make an impression on the wall of the veinsegment 20. This leaves a temporary mark 52 (see FIG. 4) on the outerwall of vein segment 20 to indicate where to place a suture. It iscontemplated that other tools or methods may be used to provide a markin a similar location on the outside of the vein segment 20.

Next, as is illustrated in FIG. 4, a needle 48 is carefully insertedinto each marked area 52 of the vein segment 20. Needle 48 is preferablythreaded with a colored suture material 50. In a desired method, theneedle 48 should not extend through the entire thickness of the veinsegment 20, but should only penetrate through a portion of the thicknessof vein segment 20. After bringing the suture 50 through the marked area52, the suture 50 is loosely secured, such by tying it into a very loosesquare knot 54 (see FIG. 5) or by using another securing technique thatallows a temporary positioning of the suture 50. The process of markingthe outside of the vein segment 20 and providing a temporary sutureshould be performed in the area of each of the commissures 26. The veinsegment 20 is now prepared for mounting to the stent 10.

If an alternative replacement material for valves is employed instead ofa bovine jugular vein segment, it will be prepared for mounting to thestent as appropriate for the particular valve chosen. For example, itmay be prepared as described in the above-cited patents issued to Cox.Thus, the particular preparation techniques described above may not benecessary for all types of vein segments, although it is desirable thatother types of vein segments are provided with some type of marking onits outer surface to indicate the location of the commissures.

One exemplary method of mounting the vein segment 20 or otherreplacement valve to the stent 10 is described below with particularreference to FIGS. 5-11. The suturing procedure described may beperformed on a mandrel or while simply manually holding the vein segment20 or other replacement valve. Use of a mandrel is particularlyapplicable if a bovine valved venous segment is employed, but may or maynot also be appropriate for other replacement valves. In the belowdescription of an exemplary process, however, a mandrel is described foruse in the mounting procedure.

First, as illustrated in FIG. 5, the vein segment 20 is slid partiallyonto a mandrel 40 (e.g., for about ¼ of the length of the vein segment20), so that the outflow end 27 extends beyond the end of the mandrel40. The stent 10 is placed over or around the vein segment 20 so that anoutflow portion 56 of the stent 10 overlies knots 54, which were made asdescribed above in conjunction with FIG. 4. The mandrel 40 is then slidfurther through the vein segment 20 and stent 10. The vein segment 20may stretch to accommodate the outer diameter of the mandrel 40, whichmay be at least slightly larger than the inner diameter of the veinsegment 20. It may be necessary in some cases to temporarily stop themovement of the mandrel 40 through the vein segment 20 in order manuallyadjust the stent 10 to keep it properly positioned relative to the veinsegment 20 and to accommodate any stretching. In any case, the mandrel40 is then moved further relative to the vein segment 20 and stent 10until the outflow end 27 of vein segment 20 no longer extends past theend of mandrel 40.

FIG. 6 shows the vein segment 20 and stent 10 as positioned completelyon the mandrel 40. At this point, the stent 10 can be adjusted toachieve a desired position of the stent 10 relative to the vein segment20 and its associated structure (e.g., the commissures 26). In order toadjust the position of stent 10, a tool such as a dull-tipped forceps58, for example, can be used to gently move the tissue of the veinsegment 20 so that the locations of the commissure tops (which werepreviously marked by knots 54), are in a desired position relative tothe stent 10. In one exemplary embodiment, the knots 54 andcorresponding tops of commissures 26 will be positioned at least 1 mmaway from the base 16 of the nearest “V” and at least 1 mm away from theadjacent arms 12, 14 of the stent 10. This positioning of the veinsegment 20 will help avoid stitching the arms 12, 14 and/or base portion16 of the “V” portions into the leaflets 22. The tops of the commissures26 and the leaflets 22 are then preferably positioned within the frameof the stent 10. In order to verify the positioning of the vein segment20, a light source can optionally be used to view the components, suchas can be accomplished by using the room light as back lighting.However, if the vein segment 20 is manipulated to the point that ittwists the commissures 26 or distorts the leaflets 22, the vein segmentmay need to be further examined and adjusted or replaced.

After the vein segment 20 is positioned as desired relative to the stent10, an area of the stent 10 nearest the outflow end 27 of vein segment20 (which may be referred generally to as an outflow end 56 of the stent10) will then be sutured or attached to the vein segment 20, asillustrated in FIG. 7. In this suturing process, the suture materialused is preferably easily visible to the human eye, and visuallydistinct such as may be provided by a suture material having a colorthat is at least somewhat darker or lighter in color than the veinsegment 20 and/or the stent 10. For example, the suture material may beprovided as a blue, 5-0 suture material. The suture material may beprovided as a monofilament or multifilament structure made of natural orsynthetic materials (e.g., nylon or polypropylene), or may alternativelyinclude an elongated metal or metal-composite thread or filament or anyother material that is suitable for permanently securing the stent to avein segment in accordance with the present invention. The suturematerial is threaded onto a needle for the suturing process.

To begin the suturing process, suture material is threaded into the veinsegment 20 under one side of the base 16 of a “V” at a location 60. Thesuture is then pulled through to the opposite side of the base 16 of the“V”, preferably leaving an extending tail 62 of suture material, whichmay be approximately 2 cm in length, for example. The suture material isthen made into a loop and the needle is threaded through the loop. Thetwo ends of suture material are then pulled to make a locking knot 64around the stent 10 at the base 16 of one of the “V”s. While it isimportant to pull the knot relatively tight, the knot should not bepulled so tight that it bends the wire of the stent 10. The suture isthen looped around one arm 12 of the “V”, such as at a location 66, byinserting the needle through the vein segment 20 under the stent 10 andadjacent to the arm 12 and pulling the suture taut. This creates a firstwhipstitch around the arm 12. The described step of inserting the needlethrough the vein segment 20 under the stent 10 is preferably repeated atleast 3 more times to create a total of at least 4 whipstitches aroundthe arm 12. Although it is possible that more or less than 4whipstitches can be used along a particular arm 12, the number ofstitches used should be sufficient to provide secure attachment of eacharm 12, 14 of the stent 10 to the vein segment 20. Each sequentialplacement of a whipstitch is positioned at a progressively furtherdistance from the locking knot 64. At the same time, each of thesewhipstitches will be placed at a distance that is progressively closerto the base of an adjacent “V” at the opposite end of the arm 12, suchas is illustrated as a location 68.

Once the next base of a “V” is reached at 68, another locking stitchshould be made around the stent 10 by again making a loop with thesuture, pulling the thread through the loop, and tightening the knotaround the base 16 at location 68. The locking stitch at the base 16 ofeach “V” should also be secured to the vein segment 20 by passing thethread at least partially through the vein segment 20 during the processof making the locking stitch. These steps will then be repeated alongeach of the arms 12, 14 around the outflow end 56 of the stent 10 untilthe suture tail 62 is reached. That is, a series of preferably at least4 whipstitches should be made along each of the arms 12, 14 around thecircumference of stent 10, with a locking stitch at each base 16,although it is possible that less than 4 whipstitches can be used alongone or more of the arms 12, 14. The whipstitches are preferablycontinuous and uninterrupted around the circumference of stent 10.

Once the suture tail 62 is reached, a final locking stitch is made. Todo this, the suture tail 62 is preferably tied off with a double throwsquare knot by wrapping the longer suture tail twice around the toolused to hold the needle (e.g., a needle holder resembling pliers) andpulling the shorter suture tail through the loops. The tying off processis preferably finalized by making a single throw square knot by wrappingthe longer suture tail once around the needle holder and pulling theshorter suture tail through the loop. The knots should both be tightenedto provide a more secure attachment. The shorter suture tail is thentrimmed at a location close to the stent 10, preferably without cuttinginto any of the stitches or tissue. The suture is then preferablythreaded under the stent 10 to pull the knot behind the stent 10. Thesuture can be trimmed relatively close to the stent 10. At this point,the structure includes stitching extending completely around the outflowend 56 of the stent 10.

While the above description provides one sequence of suture loops andknots for securing the suture material, a different series of knots andsuture manipulation may alternatively be utilized, so long as suchprocess provides a secure attachment of the stent to the vein segmentalong the various segments of the stent described herein. In particular,the knots and stitches provided in the suture should not be capable ofdisengaging from the stent and/or vein segment and should not interferewith the leaflets of the vein segment.

The above steps are then repeated at the inflow end 57 of the stent 10using a suture material that is visually distinct from the suture usedat the outflow end 56 of stent 10. For one example, white or clear 5-0suture material can be used to stitch the vein segment 20 to the inflowend 57 of the stent 10 to produce a stented valve. The suture materialused at the inflow end 57 may be the same as or different from thesuture material used at the outflow end 56, which may also be the sameas or different from the suture material used at any additionallocations where sutures are used to attach the stent to the veinsegment. The structure is illustrated as a stented valve 70 in FIG. 8,which shows a stent 10 that is stitched to the vein segment 20 aroundthe circumference of both its inflow end 57 and its outflow end 56.Although it is possible in another exemplary method of the invention tostitch the inflow end 57 to vein segment 20 before stitching the outflowend 56 to vein segment 20, another procedure and/or device would need tobe used to insure that the outflow end 56 will remain properlypositioned relative to the commissures 26 during the process ofstitching the inflow end 57.

The use of different colored sutures at the inflow end 28 and outflowend 26 of the stent 10 can assist a physician in mounting the stentedvalve in its proper orientation to its delivery device, as discussedbelow. In the event that alternative replacement valves are employed,the locations of the colored sutures may differ from that describedabove, but they preferably should be located at or adjacent to theinflow and/or outflow ends of the valve. Similarly, if alternativestents are employed, the particular stitching pattern may vary toaccommodate the specific configuration of the stent. In any of theseconfigurations, however, a visual indicator at one end of the stentand/or vein segment is preferably used to be sure to achieve the correctorientation of the valve relative to the delivery device with which itwill be used.

Following the procedure of stitching the stent 10 to the vein segment20, the stented valve 70 is removed from the mandrel 40. The edges ofthe vein segment 20 that extend beyond the stent 10 are then trimmed togenerally follow the contour of the edges of stent 10, as illustrated inFIG. 9. In an exemplary process, the vein segment 20 is cutapproximately 1 mm away from the frame of the stent 10 without cuttinginto any of the sutures. FIG. 10 illustrates the stented valve 70 aftercompletion of the procedure. For replacement valves other than bovinejugular valve segments, this trimming operation may not be required.

To provide for an even more secure attachment of the vein segment 20 tothe stent 10 and to prevent or minimize inward bowing of the walls ofthe vein segment 20, suture material may be used to provide additionallocations for attachment of the vein segment 20 to the stent 10. FIG. 11illustrates such an exemplary attachment configuration, although all ofthe attachment locations shown may not be desirable or necessary forevery stented valve. That is, either some or all of the additionalattachment locations described below may be used for a stented valve.

With particular reference to FIG. 11, suture material is used to securethe vein segment 20 at each sinus area 72, which are each locatedgenerally between the commissures. Suture material can also be used tosecure the vein segment 20 at substantially all or more preferably atthe base of every “V” (e.g., at locations 74, 76, 78, etc.). The stentedvalve 70 is preferably not on a mandrel when making these stitches andthe suture material used for these additional stitches is preferablyclear, such as a 5-0 clear suture.

One exemplary method to secure the vein segment 20 in the sinus areasincludes first locating the single “V” of the stent that is mostcentered in each sinus area 72. It is acceptable for the “V” chosen forstitching to point toward either outflow end 56 or inflow end 57 ofstented valve 70. Starting at the base of this “V”, the suture isthreaded under the stent 10 and a single throw securing square knot ismade, followed by a double throw securing knot. The vein segment 20 isthen stitched to the arms of that “V” with preferably at least 4whipstitches per arm and a locking stitch at the base of the “V” asdescribed above in conjunction with suturing the vein segment 20 to theends 56, 57 of the stent 10. As with the previously described securingprocesses, more or less than 4 whipstitches may be used, depending on anumber of factors, including the size of the stent and the length of thearms that make up its structure. In any case, the number of stitchesused should be sufficient to provide secure attachment of the stentportions to the vein segment. The suture is then tied off or terminated,preferably with three locking stitches. The resulting knot can be tuckedbehind the stent and the suture tails trimmed as close to the knot aspossible. After stitches are provided along the length of both arms, thestented valve 70 will include a “V” shaped area 79 where the stent 10 issecured to the vein segment 20, as shown in FIG. 11. This process ispreferably repeated for each sinus area of the stented valve 70. In thisprocess, if the replacement valve is other than a bovine vein segment,securement of the valve body or vein segment to the stent in the sinusareas as illustrated may not be necessary or desirable.

Next, the vein segment is secured at the bases of some or all of theremaining “V”s of the stent using the following exemplary process:First, a suture is passed through the vein segment behind the base ofthe “V”, taking care not to sew through the leaflets. A single throwknot is then made, followed with a two throw securing knot. The suturetails are then trimmed relatively close to the knot to minimize thelength of extending suture material. This process is repeated for thebase of each of the “V”s that is to be secured in this manner. When thedesired “V” bases are sutured, there is preferably no portion of thevein wall or other tubular valve body wall more than 7 mm from a suture,and more preferably no more than 5 mm from a suture. The stented valvecan then be sterilized and packaged.

By suturing the vein segment to the stent to all or substantially all ofthe bases of the “V”s, inward ballooning of the vein segment asdescribed in the article: Remblacement Valvulaire Pulmonaire par voiePercutanee: Vers une Modifiction de la Prothese, Boudjemline, et al.Arch Mal Cour 2003:96:461-6 may be avoided or controlled. With themethods and valves described herein, the suturing pattern assures thatno point on the vein wall is more than about 5 mm from a supportingsuture, particularly when all of the bases of the “V”s are secured tothe vein segment. In stents as illustrated or in stents with othergeometries, the same result could be obtained by ensuring thatregardless of the specific stent element sutured to the vein segment,there are no areas of the vein wall or other tubular valve body wallthat are more than 7 mm from a suture, and preferably that there are noareas of the vein wall or other tubular valve body wall more than 5 mmfrom a suture.

FIG. 12 illustrates a system for delivering a stented valve (e.g., thestented valve 70 of FIG. 11) to a desired implant location, such as thepulmonary vein, a valved conduit or other location. The delivery system80 comprises an outer sheath 82 overlying an inner balloon catheter (notvisible in this Figure). The outer sheath has an expanded distal portion84, within which the stented valved venous segment is located. Thestented valve is compressed around a single or double balloon located onthe inner balloon catheter. A tapered tip 86 extends from the distal endof the inner balloon catheter and serves to ease the passage of thedelivery system through the vasculature. The tapered tip 86 may becolor-coded to match the color of the suture on the stented valve thatwill be used. For example, if a blue suture material is used nearest theend of the stented valve 70 that is to be closest to the tapered tip 86,the tapered tip 86 may also be blue in color in order to provide an easyvisual indicator of the proper orientation of the valve 70. The systemmay also include a guidewire 88, which may be, for example, a 0.089 cmextra stiff guidewire as manufactured by Amplatzer, Golden Valley, Minn.The guidewire can be used to guide the delivery system to its desiredimplant location.

While the above description refers primarily to the use of coloredsuture material as a visual indicator for the orientation of a stentedvalve, another type of visual indicator, indicia, symbol or marker canbe used in addition to or instead of the colored suture materials. Forexample, the delivery system can be provided with some type of symbol,indicia, pattern, or marker that matches or otherwise corresponds with asymbol, pattern, or color on one end of the stented valve to guide theuser in properly orienting the stented valve relative to the deliverysystem. It is further possible that opposite ends of the stented valveare made to be visually distinct from each other through the use of thesame or different suture materials that are routed or stitcheddifferently on each end to provide a different visual effect. Thecorresponding delivery system includes some type of indicator thatcorresponds to one or both of the suture patterns to provide a guide tothe proper orientation of the valved stent. In another alternateconfiguration, the stented valve itself may have a geometricalconfiguration at one or both of its ends that matches a feature orfeatures on the delivery system to facilitate both proper placement andorientation of the stented valve relative to the delivery system. Thesedescribed combinations of colors, materials, patterns, and other markersthat can be used in accordance with the invention are exemplaryconfigurations, where other combinations are possible that include atleast one visual indicator on a stented valve that is provided tocorrespond with a visual indicator on its corresponding delivery system.

The delivery system and its use may correspond to that described in theabove-cited Tower, et al. applications. The delivery system is advancedto the desired valve implant site using the guidewire 88, after whichthe sheath 82 can be retracted to allow balloon expansion of the venoussegment, as illustrated in FIG. 13, as discussed below.

FIG. 13 illustrates an exemplary mechanism for deployment of the stentedvalve 70. The outer sheath 82 is moved proximally, exposing a balloon 92mounted on an inner catheter 90. The balloon 92 can then be expanded,thereby expanding stented valve 70 against the inner surface of thepreviously implanted adapter stent, stabilizing and sealing the venoussegment within the adapter stent. The balloon can then be deflated andthe delivery system withdrawn proximally.

In the case of a stented valve made using bovine jugular vein or otherpreserved biological tissue, the stented valve can be sterilized, storedand shipped separately in a buffered glutaraldehyde solution, buttypically not pre-mounted on the delivery system. However, it ispossible that the stented valve can also be pre-mounted on the deliverysystem if the system with a valve mounted thereon is similarlysterilized and kept in a sterile environment. In many cases, however,the implanting physician or an assistant will perform the step ofmounting the stented valve 70 to the balloon 92. Because it is notalways easy to visually determine which end of the valve is the outflowend, there is a possibility that the valve might be placed incorrectlyon the balloon, which would result in an unacceptable implantationprocedure. In the embodiment illustrated, however, the suturing 100 atthe outflow end 56 of the stent 10 is easy to identify because it isblue in color to preferably correspond to a blue color of the adjacenttip 86. So long as the person mounting the valve to the balloonremembers to match the color of the suture material at the outflow end56 of the stent 10 to the color of the tip 86, the possibility of amistake is minimal.

In addition, as described in the above-cited Tower, et al. patentapplications, the inner catheter 90 may be provided with a collar 94,which is intended to engage the proximal end of expanded distal portion84 of the outer sheath 82. The collar may be white, corresponding to thesutures 102 that are white or clear, for example, and located at theinflow end 57 of the stent 10 adjacent the collar, further assisting inproper location of the stented valve 70. While the colored markings onthe stented valve are provided by means of colored sutures in thepreferred embodiment described above, other methods of marking, such ascolored inks or dyes or other colored components might be used insubstitution for or in addition to colored suture material.

The present invention has now been described with reference to severalembodiments thereof. All patents, patent applications, publications andjournal articles mentioned herein are incorporated herein by referencein their entirety. The foregoing detailed description and examples havebeen given for clarity of understanding only. No unnecessary limitationsare to be understood therefrom. It will be apparent to those skilled inthe art that many changes can be made in the embodiments describedwithout departing from the scope of the invention. Thus, the scope ofthe present invention should not be limited to the structures describedherein, but only by the structures described by the language of theclaims and the equivalents of those structures.

The invention claimed is:
 1. A prosthetic valve and delivery system, thevalve mountable to the delivery system in either first or secondorientations, wherein the prosthetic valve comprises: a valve member; anexpandable stent having a first portion and a second portion; and aplurality of sutures holding the valve member to the stent at the firstand second portions, wherein the sutures at the first portion arecolored differently than the sutures at the second portion; wherein thedelivery system includes at least one colored visual indicator thatcorresponds with the sutures at the first portion of the stent, whereinthe colored visual indicator is generally the same color as the suturesat the first portion of the stent; and wherein the at least one coloredvisual indicator is located such that when the prosthetic valve ismounted in the first orientation relative to the delivery system, the atleast one colored visual indicator is adjacent to the first portion ofthe stent.
 2. The prosthetic valve and delivery system of claim 1,wherein the first orientation of the prosthetic valve relative to thedelivery system corresponds to a correct valve orientation, and whereinthe second orientation of the prosthetic valve relative to the deliverysystem corresponds to an incorrect valve orientation.
 3. The prostheticvalve and delivery system of claim 1, the expandable stent furthercomprising an intermediate portion between the first and second portionswherein the plurality of sutures include an intermediate suture locatedat the intermediate portion to attach the valve member to the stent atthe intermediate portion.
 4. The prosthetic valve and delivery system ofclaim 1, wherein the colored visual indicator is a symbol.
 5. Theprosthetic valve and delivery system of claim 1, wherein the coloredvisual indicator is a pattern.
 6. The prosthetic valve and deliverysystem of claim 1, wherein the first portion of the stent comprises aninflow end of the prosthetic valve.
 7. The prosthetic valve and deliverysystem of claim 1, wherein the first portion of the stent comprises anoutflow end of the prosthetic valve.